The present invention relates to a workpiece support device capable of adjusting a projection amount of a support rod supporting a workpiece from a support stand.
When predetermined workings such as processing and inspecting are performed to a workpiece such as a material to be processed or a material to be inspected, a workpiece support device capable of supporting a workpiece from a lower side so as not to block such workings is used in some cases. The workpiece support device may have such a constitution that rods abutting on the lower side of the workpiece to support it from the lower side are incorporated reciprocably. Therefore, when the workpiece is supported, the rods are made to project up to a predetermined support spot and the rod can be retracted up to a retreat position after completion of the workings. When the workpiece must be stably supported in its horizontal state due to necessity in the processing or inspecting working or the like, the workpiece may be supported at a plurality of spots by using a plurality of rods. In this case, it is necessary to adjust a support spot, i.e., a projection amount of each rod in accordance with concavity and convexity on each of abutment portions with which the respective rods contact.
Conventionally, a technique as disclosed in Patent Document 1 (Japanese Patent Laid-Open Publication No. 9-225764) is one in which a pad whose bottom face serves as an inclined face is fixed to a base end portion of a rod and a wedge-shaped block arranged on a lower side of the pad is slid along the inclined face of the pad and thereby a projection amount of the rod is adjusted. Additionally, a technique as disclosed in Patent Document 2 (Japanese Utility Model Laid-Open Publication No. 3-44534) is one in which an advance-side pressure chamber is partitioned and formed on a lower end face side of a piston fixed to a rod and the rod is made to project until contact with a workpiece by allowing a flow and injection of hydraulic fluid from an externally disposed hydraulic-fluid supplying portion to the pressure chamber, and a projection amount of the rod is fixed by stopping the supply of the hydraulic fluid after the contact.
According to the technique disclosed in Patent Document 1, since the rod is moved upward or downward by moving horizontally the wedge-shaped block, a space for moving the wedge-shaped block is necessary for being ensured in the horizontal direction, which results in an increase of size of the workpiece support device. Therefore, it is difficult to arrange a plurality of rods at a narrow spacing and it is difficult to support stably the workpiece with significant concavity or convexity or the thin, easily deformable workpiece.
According to the technique disclosed in Patent Document 2, the advance-side pressure chamber and the working oil supplying portion externally disposed are connected to each other by a pipe, and the working oil from the working oil supplying portion via the pipe is made to flow and be injected at the timing of an intention to make the rod project. Therefore, there is a possibility that the working oil will be leaked from a connection portion of the pipe or the like to contaminate a periphery thereof. Also, since the rod pushes up the workpiece from beneath by the hydraulic pressure supplied to the advance-side pressure chamber, support spots for the workpiece fluctuates easily. Accordingly, a thin and easily deformable workpiece may be deformed.
An object of the present invention is to provide a workpiece support device capable of adjusting a projection amount of rod and supporting stably workpieces with various shapes or easily deformable workpieces.